The striate cortex of one cerebral hemisphere of a rhesus monkey is removed surgically under direct vision. The monkeys are allowed to recover from the effects of surgery in a normally lit environment. The monkeys are then trained on a series of tasks requiring visual perception and visually-guided eye movements. They are then prepared for chronic neurophysiological recording and for eye position recording. The activity of single neurons in the frontal eye fields and posterior parietal cortex both ipsilateral and contralateral to the lesion is studied. The monkey's oculomotor capacity is studied quantitatively. The frontal eye fields are much less visually responsive than normal although eye movements can still be evoked at low threshold from the silent area. The animals can make normal saccadic eye movements to stationary targets in the blind field although they cannot make accurate saccades to moving stimuli. They cannot use stimulus velocity or position information in the contralateral field to generate a smooth pursuit eye movement. These data indicate that the striate cortex is necessary for the normal functioning of visual association areas, including those involved in oculomotor processing.